Coating of tips for electrochemical scanning tunneling microscopy by means of silicon, magnesium, and tungsten oxides

Salerno, Marco
September 2010
Review of Scientific Instruments;Sep2010, Vol. 81 Issue 9, p093703
Academic Journal
Different combinations of metal tips and oxide coatings have been tested for possible operation in electrochemical scanning tunneling microscopy. Silicon and magnesium oxides have been thermally evaporated onto gold and platinum-iridium tips, respectively. Two different thickness values have been explored for both materials, namely, 40 and 120 nm for silicon oxide and 20 and 60 nm for magnesium oxide. Alternatively, tungsten oxide has been grown on tungsten tips via electrochemical anodization. In the latter case, to seek optimal results we have varied the pH of the anodizing electrolyte between one and four. The oxide coated tips have been first inspected by means of scanning electron microscopy equipped with microanalysis to determine the morphological results of the coating. Second, the coated tips have been electrically characterized ex situ for stability in time by means of cyclic voltammetry in 1 M aqueous KCl supporting electrolyte, both bare and supplemented with K3[Fe(CN)6] complex at 10 mM concentration in milliQ water as an analyte. Only the tungsten oxide coated tungsten tips have shown stable electrical behavior in the electrolyte. For these tips, the uncoated metal area has been estimated from the electrical current levels, and they have been successfully tested by imaging a gold grating in situ, which provided stable results for several hours. The successful tungsten oxide coating obtained at pH=4 has been assigned to the WO3 form.


Related Articles

  • Void formation on ultrathin thermal silicon oxide films on the Si(100) surface. Wei, Yi; Wallace, Robert M.; Seabaugh, Alan C. // Applied Physics Letters;8/26/1996, Vol. 69 Issue 9, p1270 

    The formation of voids on the thermally grown (650 °C) ultrathin (∼1 nm) silicon oxide films on the Si(100) surface was investigated by using ultrahigh vacuum scanning tunneling microscopy. Voids form randomly on the ultrathin oxide film upon thermal annealing at 750 °C. In contrast...

  • Phisicochemistry of Alkaline-Earth Metals Oxides Surface. Ekimova, Irina; Minakova, Tamara; Ogneva, Tatyana // AIP Conference Proceedings;2015, Vol. 1698 Issue 1, p1 

    The surface state of alkaline-earth metals and magnesium oxides obtained by means of commercial and laboratory ways has been studied in this paper. A complex of methods has been used for identification, determination of a phase composition and morphology of the samples. The high basic character...

  • A convenient method for removing surface oxides from tungsten STM tips. Hockett, Lisa A.; Creager, Stephen E. // Review of Scientific Instruments;Jan1993, Vol. 64 Issue 1, p263 

    A convenient treatment that can be applied to tungsten scanning tunneling microscope tips prepared by electrochemical etching in aqueous base is described. The treatment removes the majority of the tungsten oxide layer present after etching and produces a very stable tunnel junction and a high...

  • Electrochromic writing and erasing on tungsten oxide films in air by scanning tunneling microscopy. Qiu, H.; Lu, Y. F.; Mai, Z. H. // Journal of Applied Physics;1/1/2002, Vol. 91 Issue 1, p440 

    The scanning tunneling microscope (STM) was used for both spot coloring and bleaching on α-WO[sub 3-x] thin films. By wetting the STM tip with 1 M KOH solutions or de-ionized water before the tip approached, and keeping the humidity higher than 40%, the electrochemical reaction occurred at...

  • Bilayer gate dielectric study by scanning tunneling microscopy. Ong, Y. C.; Ang, D. S.; Pey, K. L.; O’Shea, S. J.; Goh, K. E. J.; Troadec, C.; Tung, C. H.; Kawanago, T.; Kakushima, K.; Iwai, H. // Applied Physics Letters;9/3/2007, Vol. 91 Issue 10, p102905 

    An advanced bilayer gate dielectric stack consisting of Sc2O3/La2O3/SiOx annealed in nitrogen at 300 °C was studied by scanning tunneling microscopy using bias dependent imaging. By changing the sample bias, electrical properties of different layers of the dielectric stack can be studied. At...

  • Direct writing of submicron metallic features with a scanning tunneling microscope. Silver, R. M.; Ehrichs, E. E.; de Lozanne, A. L. // Applied Physics Letters;7/27/1987, Vol. 51 Issue 4, p247 

    We demonstrate for the first time that the scanning tunneling microscope can be used to write metallic features on a surface without further process steps. Using organometallic gases we have obtained features down to 20 nm in size.

  • Tungsten Oxide Nanoporous Structure Synthesized Via Direct Electrochemical Anodization. Ismail, Syahriza; Razak, Khairunisak Abdul; Jing, Pang Woei; Lockman, Zainovia // AIP Conference Proceedings;5/25/2011, Vol. 1341 Issue 1, p21 

    Room temperature anodization of tungsten (W) was conducted in 1 M Na2SO4 added with NH4F. Nanoporous tungsten oxide (WO3) layer was produce when pH of the electrolyte was 3. The growth of the porous WO3 was further investigated in bath with varying pH and the possible explanation for the...

  • Analysis of SiO[sub 2]/Si(001) interface roughness for thin gate oxides by scanning tunneling microscopy. Gotoh, Masahide; Sudoh, Koichi; Itoh, Hiroyasu; Kawamoto, Kazunori; Iwasaki, Hiroshi // Applied Physics Letters;7/15/2002, Vol. 81 Issue 3, p430 

    We studied the interface roughnesses of SiO[sub 2]/Si(001) for gate oxides of 8 and 15 nm thicknesses together with RCA-treated samples by using scanning tunneling microscopy (STM). By STM observation and scaling analysis we made clear that the interface roughnesses of thermal oxides/Si...

  • Quantitative characterization of physical processes during nanometer surface modification. McBride, S. E.; Wetsel, G. C. // Applied Physics Letters;12/24/1990, Vol. 57 Issue 26, p2782 

    A scanning tunneling microscope developed for microscopy, spectroscopy, and lithography has been used for modification of metallic surfaces exposed to the atmosphere. We report here the first quantitative characterization of a submicrometer area of a metallic sample before and after pulsing the...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics